Association between physical activity and Lipoprotein(a) levels in school children: Interim results from Hand aufs Herz Study

Background Lipoprotein(a) [Lp(a)] levels are primarily determined by genetic inheritance, with 80-90% of variation attributable to parental genes. While physical activity positively influences many aspects of lipid metabolism, Lp(a) remains a notable exception, as its levels are genetically fixed and do not fluctuate with lifestyle changes. Purpose This study aims to assess how Lp(a) levels are associated with physical fitness in German children and adolescents. Methods The ‘Hand aufs Herz’ is an ongoing cardiovascular health study for screening school children. Cross-sectional data on Lp(a), physical activity patterns, fitness, and anthropometric measures were collected using standardized protocols and self-reported questionnaires. Children with valid Lp(a) measurements and physical activity information were included in the analysis. To evaluate the combined effects of physical activity (per day), fitness, sports club membership, and demographic variables on Lp(a) levels, a multiple linear regression model was constructed using log-transformed Lp(a) values in R software. (v4.4.1). Results The analysis included 273 (139 boys and 139 girls) children and adolescents aged 8 to 19 years with valid Lp(a) measurements and data on different physical activity variables. The overall regression model with multiple sport factors as influencing factors, Lp(a) levels as outcome, and age, sex, and BMI z score as potential confounders did not find any association (p = 0.1765, adjusted R² = 0.0139). Specifically, compared to the "< 1 hour" baseline group, neither the "1-2 hours/day" (estimate = -0.32, p = 0.113) nor the "more than 2 hours/day" category (estimate = 0.22, p = 0.927) showed a significant impact on Lp(a) levels. Similarly, fitness level did not seem to be a relevant predictor of Lp(a) levels: the "very good physical fitness" group did not differ significantly from the "bad physical fitness baseline group (estimate = 0.34, p = 0.061). Conclusion These results suggest that, in this cohort, factors such as physical activity, fitness, and demographic characteristics do not significantly influence Lp(a) concentrations, indicating that genetic factors likely play the predominant role in regulating Lp(a) levels. However, further research with a larger sample size, including more children and adolescents, is needed to confirm these findings and explore potential interactions that may become apparent with increased statistical power.